“…If λ n = λ n , α n = α n , n = 1, 2..., L = L. Thus the specification of the spectral data Ω = {λ n , α n } ∞ n=1 uniquely determines the operator L.Proof. Under the hypothesis of the theorem we obtain, in view of(11), thatM (λ) = M (λ) on consequently by Theorem 1, L = L. ◀ If λ n = λ n and µ n = µ n , n = 1, 2..., then L = L. Thus the specification of two spectra {λ n , µ n } ∞ n=1 uniquely determines L.Proof. It is obvious that characteristic functions ∆(λ) and ψ(0, λ) are uniquely determined by the sequences{λ n } ∞ n=1 and {µ n } ∞ n=1 , respectively.…”